I had a bit of a shock on Saturday. Long drive up from Dublin to Belfast. Stop briefly at a shop, and then carry on. About 5 minutes after leaving the shop, I pull up at a set of lights, and notice at tickover (6-700 rpm), the oil pressure on my Eunos had dropped down to something like 1 kg/cm or less! Water temperature was slightly into the hot zone. I drove on up a motorway at 70ish (like we all do). Oil pressure was about 4 kg/cm; it jerked around momentarily (3.8-4). At the next roundabout, the oil pressure was back to a normal 2 kg/cm at tickover, and water temperature back in the middle of the range. I checked the oil level when I got back, and it was at the full mark, so no sign really of oil being burnt or being lost somewhere (not a drip on the drive). Last oil change was about 4000 miles ago with Mobil oil. Now this has happened once before to me; last year whilst waiting to board a ferry, with the engine running.

Does this mean:
1. My engine has had it.
2. Oil pump worn?? The car has done 86000 kms.
3. Engine needs an oil way flush.(it sounds a little clattery on cold starts, but this soon goes away).
4. Ignore, don't worry about it. What do we need gauges for anyhow?;-) (12/99)

When did your oil filter last get changed? Also 600-700 rpm is very low. Try and aim for 850. I always set mine so that the TEN wire makes no difference. (12/99)
. was it actually the gauges not the oil/water .. what did the fuel gauge do .. if it was anywhere off the bottom! .. sounds more like the problem to me .. temperatures and pressures do not jump that massively. .. you will hear the difference .. and smell it. (12/99)

I changed my oil and filter at the weekend. I have noticed that the oil pressure seems to be a little higher in all situations. (i.e. starting from cold, under load, idling)

Is this unusual when changing to fully synthetic oil? New oil is Halfords fully synthetic 5W/40 as recommended on the list. Old oil was apparently Valvoline semi-synth. New filter is Mazda OEM. Old one was a third party design. (Last oil and filter change done by garage.)

Oh, and by the way, used the tip of removing engine under-fairing and fuel inlet manifold support bracket for easy access to filter from below the car. Makes it so easy - definitely recommended! (2/00)

I changed my oil and filter last week to Halfords fully synthetic. I didn't use an OEM filter, it was a Champion one from Halfords. Didn't notice what make the old one was though.....

MY oil pressure is now lower. I wish I had known about the tip. My bruises have just about gone and my skin has grown back now!

Since servicing my car, it has run a lot better generally, and seems faster/smoother. The only problem is when I leave it at work. I leave it for nearly 13 hours whilst on shift, and when I start her up and pull off she's very lumpy, especially after I have changed gear and the revs have dropped off, until the engine warms up. This "seems" to have got worse since the service.

Any ideas anyone? BTW I changed the plugs and they were preset to 1mm - I did check them. (2/00)
Oil gets thinner with age as long molecules get chopped up and cooked up .. or was the grade different ... I noticed this when going from thick but old Mobil 1 to thin/French Mobil 1. (2/00)
Set your manual idle by grounding out the diagnostic wire .. I forget which! .. if this fails force it too idle a bit high in this mode .. the ECU can still pull 200 rpm or so down. (2/00)

I seem to be having a problem with my oil pressure and need some advice.

Last night I was driving on the motorway when I noticed my oil pressure had dropped from its usual 3 Kg/cm3 at 70 mph to about 1.8-2. When I stopped the oil pressure dropped to 0 at idle (usually 1.8) and would only rise to 2 when pulling away (usually goes up to 4).

I stopped to check the oil level and it was full, I couldn't spot any leaks, there was no smoke from anywhere and no smell of oil in the car. All other gauges read at their normal levels.

After stopping for a couple of hours the gauge went back to its normal behaviour until I hit the motorway on the way home and the same thing happened again. Has anybody seen anything like this before? Could this be a problem with the engine that I should get somebody to look at or could it be a problem with the gauge or the sensor where ever that is?

The car is a 90 Roadster with 84000KM. The last service was at 78000KM back in September. I would appreciate any advice anyone has. (4/00)
Probably not a big problem. You will find that the oil has lost some of its stickiness, in particular when hot. If you are worried change the oil & filter. I think most do this every 3,000 miles anyway, particularly if you drive hard or in hot conditions. (4/00)
I am wondering if anyone can help me with a problem with a newly purchased 'M' reg import MX5. On three occasions since purchasing the car 2 weeks ago I have had trouble starting the engine and when I do manage to get it going the oil filter distorts and releases engine oil everywhere! I have replaced the engine oil and flushed the system through and replaced oil filter. Has anyone else had this problem? (7/01)
Do they have a presure relief valve, ie to stop too much presure building up, and is it stuck, just guessing. (7/01)
Either, the filter is going on wrong, or the wrong filter. Blocked crankcase breather, causing the oil to surge? Maybe when he changes the oil, crank over the engine with the fuel ig. fuse removed, to get the oil pressure up. New set of leads might help, to eliminate any variables in the ignition side of things. (7/01)
Leads wont make any difference. (7/01)
Unless he has a coincident ignition problem, since he has starting problems. (7/01)
But that wont make any difference to his "distorting" oil filter, IMHO of course, I did not read his email properly as I missed his starting problems, but I wouldn't be surprised if they were not both related. (7/01)
Oil pumps in engines always have a pressure release valve to stop potentially enormous pressure building up in the oil system. If this valve has stuck shut, that could be your problem - I'll just check in my manual. Yes it looks as though this valve is serviceable without dismantling the whole front of the engine. No I lied it's a sump off job (ugh) Does the oil pressure gauge fly off the right of the screen (or do you have the later 'idiot' gauge which will look fine) In the mazda book page D-11 its called pressure control spring/plunger etc & it's released by pulling out a split pin. Hope this ain't your problem! This is for mk1 1600 engine & mazda workshop manual (7/01)
Could this initial problem the oil filter distorts and releases engine oil everywhere! be as simple as the 'O' ring being dislodged, coupled with a separate starting problem? (7/01)